Have a squirrel with half of a tail and about a week or two behind my other 4 squirrels (approx 11-13 weeks old vs his 9-10). Three are from same litter and fourth added to outdoor enclosure. He is the only male and gets attacked by the others when I try to introduce them. Any ideas? I hate that he has no companions and is in an enclosure by himself. Tried introducing one at a time without food or water to fight over, but gets nasty, fast. He is never the aggressor.